1. Field of the Invention
This invention relates to apparatuses for recording and reproducing a digital signal, and more particularly, to an apparatus for re-recording a digital signal which adds a discriminating signal to the previously recorded digital data to prevent erroneous error correction.
2. Description of the Prior Art
In a digital tape recorder, when new data is recorded over data which has been previously recorded, or when new data is recorded in a track after the first recorded data has been erased, the accumulation of dust on the tape can cause an erasing omission or recording omission so that the new data is not properly recorded. After the re-recording operation has been performed, and the dust is removed from the surface of the magnetic tape, the originally recorded data is included with the new data on the track where the dust had previously accumulated. When the original or first recorded data is reproduced along with the new data, it is difficult to detect such a condition and the resulting influence upon the signal processing.
When a re-recording operation is performed with dust accumulated on the magnetic tape, a significant length of the tape, for example, as much as 200 microns, may not be properly recorded.
By reason of the foregoing, in the case of an audio pulse coded mudulation tape recorder, abnormal sounds may be generated when the first recorded data is reproduced along with the new data.